The present invention relates to a semiconductor pressure sensor for use on automotive vehicles for measuring an intake vacuum in the engine, and more particularly to such a semiconductor pressure sensor which is constructed to reduce electromagnetic interference and prevent entry of moisture into the sensor.
Various systems for electronic control of automotive engines are in use today. One such system includes a pressure sensor for detecting an intake vacuum in the engine to control the air-fuel ratio of an air-fuel mixture to be supplied to engine cylinders. For stable operation of the electronic control systems or devices, they are required to be protected against electromagnetic radiation from an increasing number of different sources such as mobile radio transmitters, radio and television broadcasting stations. To meet the above requirement, it is important that electronic control units and sensors of the devices be immune to electromagnetic interference (generally abbreviated as "EMI").
The pressure sensor is normally mounted on a printed circuit board. Since the printed circuit board is subjected to erosion due to moisture, it is necessary to protect the printed circuit board from moisture attack which would otherwise take place along lead wires connected to the printed circuit board.